Valve control mechanism



Nov. 16, 1954 F. w. MCRAE VALVE CONTROL MECHANISM Filed Aug. 16, 1952F950 U. M: 1645 INVEN TOR.

United States Patent 9 2 Claims: (G1. 137-460.);

This invention relates to: improvements in'valvecom trol mechanisms.

An object of. the inventionsisto provide a construction wherein there.is a. normally-- open valve closure urged into closed. positioneither'bygravityor otherwise,v

and which is.releasablyheldiin open positionand controlled by amechanism responsive to the'rate of flow through the valve;

Valves of this type have a large variety'of: different For example, thecombination embodying the present invention may be incorporated" inapipe liner Theleading from a large ammonia storage tank. pressure atwhich the ammonia is maintained in the storage tank may vary widely; Ifsuch a line in which thepresent valve is incorporated leads-from:thestoragetank to a compressor, the compressor will draw ammonia from thestorage tank at a predetermined rate with very little variation. Intheevent'that the pipe line leading from thestorage.tank.to-the.compressorshould break, the rate of flow through thevalve would'materially increaseand it would be desirableto:immediately-close.

the'valve so that.all.of.the.arnmonia in'the storage tank would not bepermittedtoescape, It will be appreciated that under such.circumstances. where: the pressure in the storage.:tank..may. varyconsiderably that the control mechanism thatefiects.a.closing.-:of;'the:valve should be largely independentof..pressure..variations. but should 'be immediately responsive. to.material variations in= the rate of flow through. the valve.v

An object of the present invention is to provide a valve controlmechanism that satisfactorily meets all of these requirements.

Another object of the invention is to provide a valve control mechanismhaving the above-mentioned characteristics wherein the valve can beclosed if desired manually or from remotely located control points.

With the foregoing and other objects in view, which will be mademanifest in the following detailed description and specifically pointedout in the appended claims, reference is had to the accompanyingdrawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a longitudinal vertical section through a constructionembodying the present invention; and

Fig. 2 is a vertical section taken substantially upon the line 2-2 uponFig. 1.

Referring to the accompanying drawings wherein similar referencecharacters designate similar parts throughout, the improved constructioncomprises a valve body or housing having an inlet 11 and an outlet 12.The inlet and outlet are preferably flanged to cooperate with companionflanges on the pipe line or conduit Within which the body is adapted tobe inserted. Within the body there is disposed a valve seat 13engageable by a closure 14 that is loosely mounted on a swingable arm15. This swingable arm is mounted on a transversely ex tending pintle16, a portion of which preferably extends through the wall of thehousing 10 to the exterior thereof so that it may be rotated from theexterior of the housing to swing the closure into open position. Theclosure 14 is normally held in open position by means of a latch 17pivotally mounted on a pin 18 that is supported on ears 19 within thehousing. This pivoted latch has a dog 20 engageable with a finger 21 onthe arm to releasably hold the closure in open position. The latch Inthis manner; if the rate of flowthrough the valve varies materiallyfromapredetermined' orset rate. the valve. will be caused toautomaticallyICC Z 1.74; has:- at; weight: 225 that .urgesithe. latch. to swing in:a. counterclockwise direction-as.viewecbiniFig.. l', toreleasethe-i.closure.=. The..closure:.1i4; is. adapted" to swing bygravity orpitzmay befurgedbyi a2 springzinto'. closing 'posi tionagainst :the;seatr 13;

Thee abovedscribed construction is not. new "in the art and; ittwill?be? appreciatedtlthatother types of self closing valves maybe'isubstituted itherefor'if 3 desired:

In association. with: the: valve: there is: :an'a orifice .plate: 23having: an. orificet24i 'therein. Thisaorifice plate-is illustrated asbeing replaceably clamped between. the.- downstream end of. the body"101 and the t adjacentr companion: flange: on the-conduit. The: orificeplate :may' be: removed and. replaced with. other: plates=having-larger: or smaller: orifices ttherein tormeettvarious conditionssUpstream with. respect". to the? orifice plate: there isa. tubing. 25:connected as: at 261 to. thevinterior 'of the housing 10: and serving:to'conduct pressureto a dia phragm' housing. generally" indicatedi at.27. Down-- stream:.with' respectitoa the orifice plate 23 there" is asimilar tubing '28 connectedftot the interior ofthecon'-- duitandserving. to conductrpressure: to: the: diaphragm housing v271 Thistubings'may have aalthree way 'solenoid valve 29 incorporated therein"for:' a purpose; h'ereinafter tozbe. described.

The.. diaphragm: housing: 27 is divided into two' compartments-or:chambers? 3lliand; 31 by a.=diaphragm 32. The tubing 28leads-:to"the-:chambersSOf andithe'tubing 25: leads to: the chamberr31iA compression spring 33 urges"the?diaphragm"325downwardly; 'and thepressure "exerted by-this springnion the .diaphragm' mayrbeadjusted.- bymeans of a threaded plug 34. 35 indicates merely a. closure: plug" forthe top." of. the. diaphragm housing which maybe:removedtfor"thespurposeflof adjusting the: plug-13A-andiconsequentljc the pressure: exerted by thespringi33ionithesdiaphragmz.

Abovex.the-=latch r 17 "theretissav slida-ble pin 36 that en'- gagesthe-lop: of tliedatchz with. pin: is equipped" with? a-zhead 38 and:is.= surrounded by meansaofi'a compression". spring139! .hich urges thepin upwardly. The heart 38*; engages. a-pim 40 that slida-bly extends 7through an gland. 41" with" aw relatively closer fit: The.-upper'end ofthisapim is;engageab le: -with1a stud. 42 our the; under rside: of thediaphragm.

In; the normah position the closure 14'iiselatched i in" its 4opencpositiomby thelatch lflr. Variationsin pressure in: the ammoniatank or in the fluid supplied to the valve have no noticeable effect onthe valve. Thus, a high increase in pressure is conducted through boththe tubes 25 and 28 to opposite sides of the diaphragm 32 and arebalanced or substantially so. Conversely, a decrease of pressure iseffective through the tubes 25 and 28 on opposite sides of the diaphragmwithout aifecting it. Under normal conditions a compressor downstreamwith respect to the orifice plate 23 will draw ammonia from the supplytank through the valve at a predetermined rate. As long as this ratepersists there will be a slight dif ferential in pressure created by theorifice plate. Thus, the pressure transmitted to the diaphragm housingthrough the tube 25 will be slightly greater than the pressuretransmitted through the tube 28. This slightly higher pressure in thechamber 31 than the pressure that exists in the chamber 30 would urgethe diaphragm 32 upwardly. Such upward movement, however, is opposed bythe compression spring 33. Consequently, under normal conditions, whilethe compressor is drawing fluid at a predetermined rate there is notripping or actuation of the valve.

On the other hand, if the pipe line downstream from the orifice platebetween the orifice plate and the compressor should break this wouldpermit flow through the valve to occur at a very materially increasedrate. The difierential in pressures in the tubes 25 and 28 wouldconsequently increase so that the pressure in the chamber 31 would besufiiciently higher than the pressure in the chamber 30 to cause thediaphragm to lift against the pressure of the spring 33. When thediaphragm is lifted it permits the pin 36 to be elevated by its spring39, thus permitting the weight 22 to rotate the latch 17, allowing theclosure 14 to immediately close and seat against the seat 13. In thisway, in the event that the pipe line leadmthe housing 10. This 1 ing tothe compressor should break or become damaged the valve will be causedto automatically close to prevent further escape or loss.

The valve may be manually or intentionally tripped by means of thesolenoid valve 29. The electric conductors leading to the solenoid ofthis valve may be connected to any electric switch located in theimmediate neighborhood or at a remote control point. When this solenoidvalve is energized by closing the electric circuit through its solenoidits effect is to shut off the tube 28 and open the chamber 30 toatmosphere. Any ammonia that may be in the chamber 30 and in thatportion of the tube 28 that is between the solenoid valve 29 and thediaphragm housing 27 is lost to atmosphere but its volume is negligible.

From the above-described construction it will be appreciated that animproved valve control mechanism is provided which is not influenced byvariations in pressure in the fluid conducted therethrough but which isinfiuenced by variations in the rate of fiow therethrough. Consequently,any increase or decrease in the pressure of the fluid supplied to thevalve does not cause it to trip. But in the event that some circumstancecauses the rate of flow through the valve to materially change the valvewill be automatically tripped and caused to close.

The tubings and 28 may have manually operable valves inserted therein ifdesired so as to isolate the diaphragm housing from the line during theperiod that the pipe line is being filled. When the line has been filledand conditions have been more or less stabilized in accordance withnormal operations, such manual valves, not shown, may be opened and leftopen.

Various changes may be made in the details of construction withoutdeparting from the spirit and scope of the invention as defined by theappended claims.

I claim:

1. A valve operable to shut off when flow therethrough exceeds apredetermined rate comprising a valve body having an inlet and an outletand a valve seattherebetween facing toward the inlet, a valve closureswingably mounted in the body adapted to seat upon said seat, a latchpivotally mounted in said body engageable with the closure to releasablyhold the closure in open position, said latch being biased to releasethe closure, a diaphragm and housing therefor on the exterior of thebody, means operatively connecting the diaphragm and the latch through awall of the body whereby the diaphragm may hold the latch in oppositionto the bias thereon in engagement with the closure, means for creating apressure differential in the flow of fluid that passes through the body,and means for conducting the differential pressures to opposite sides ofthe diaphragm in such a manner that as long as the pressure differentialdoes not exceed a predetermined degree the diaphragm will hold the latchin engagement with the closure but when the differential exceeds apredetermined degree the diaphragm will allow the latch to release theclosure and thus allow the closure to close.

2. A valve operable to shut off when flow therethrough exceeds apredetermined rate comprising a valve body having an inlet and an outletand a valve seat therebetween facing toward the inlet, a valve closureswingably mounted in the body adapted to seat upon said seat, a latchpivotally mounted in said body engageable with the closure to releasablyhold the closure in open position, said latch being biased to releasethe closure, a diaphragm and housing therefor on the exterior of thebody, means operatively connecting the diaphragm and the latch through awall of the body whereby the diaphragm may hold the latch in oppositionto the bias thereon in engagement with the closure, said means includinga spring exerting pressure on the diaphragm in a direction to cause saidmeans to allow the latch to release the closure, a spring in thediaphragm housing arranged to exert pressure on the diaphragm inopposition to the mentioned spring, means for adjusting the pressureexerted by the last-mentioned spring, means for creating a pressuredifferential in the flow of fluid that passes through the body, andmeans for conducting the differential pressures to opposite sides of thediaphragm in such a manner that as long as the pressure differentialdoes not exceed a predetermined degree the diaphragm will hold the latchin engagement with the closure but when the differential exceeds apredetermined degree the diaphragm will allow the latcli to release theclosure and thus allow the closure to c ose.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 665,181 Confer Ian. 1, 1901 1,478,320 Baxter Dec. 18, 19231,787,686 Kerr Jan. 6, 1931 2,182,873 King Dec. 12, 1939 2,327,055McMahon Aug. 17, 1943 2,357,133 Rider Aug. 29, -1944 2,587,358 McRaeFeb. 26, 1952 2,613,683 Baird Oct. 14, 1952

